What is the ruling on dedicating (waqf) property to males, generation after generation, to the exclusion of females, such that the inheritance reverts to the male cousins in the event of the original family line having no male descendants, and how is the inheritance to be handled after the death of the endower?

Tahbis is an endowment (waqf), and it is a beneficial act of proximity [to Allah] and an ongoing charity (sadaqah jariyah) whose reward continues after the death of the giver, based on the Prophet, peace and blessings be upon him, saying: "When a person dies, all his deeds come to an end except for three: an ongoing charity, knowledge from which others benefit, or a righteous child who supplicates for him." The condition of the one who establishes the waqf must be adhered to, and it is not permissible to violate it. This includes if he endows wealth for the males of his descendants but not the females, even though it is better not to deprive females. This specific allocation is valid if it is for a legitimate reason and not merely a preference, just as Abu Bakr al-Siddiq allocated a charity to Aisha, and Umar allocated his waqf to Hafsa without her brothers.

Therefore, the aforementioned waqf is valid, and the condition of the endower must be observed. If the male lineage of the original family ceases, the waqf transfers to the male cousins of the family, according to the condition of the endower.